Nuclear Biosphere

It’s all about risk and probability

In my last three articles, I addressed risk of nuclear energy from different perspectives such as low dose radiation, nuclear plant accidents and waste storage strategies. Here is an overall summary to the ‘risk’ of nuclear energy. I credit Gary Was, Professor of Nuclear Engineering and Radiological Sciences at University of Michigan for validating my knowledge of nuclear science and technology. The following are extractions from his writings that I have stated before.

Nuclear power is likely the least well-understood energy source in the United States. Just 99 nuclear power plants spread over 30 states provide one-fifth of America’s electricity. These plants have provided reliable, affordable and clean energy for decades. They also carry risk – to the public, to the environment and to the financial solvency of utilities.

Risk is the product of the probability of an occurrence and its consequence. The probability of dying in a car accident is actually quite high compared to other daily events, but such accidents usually claim few individuals at a time, and so the risk is low. The reason nuclear energy attracts so much attention is that while the probability of a catastrophic event is extremely low, the consequence is often perceived to be extremely high.

Nuclear power’s safety record is laudable, considering that nuclear plants are running full-tilt. The average capacity factor of these plants exceeds 90%; that means 99 plants are generating full power over 90% of the time. If you compare that to any other energy form, there’s a huge gap. Coal is a mainstay of electricity generation in this country and has a capacity factor of around 65%. Gas is about the same; wind’s capacity factor is around 30%, and solar is at 25%.

Three Mile Island in 1979, Chernobyl in 1986 and Fukushima in 2011 accidents had serious, lasting consequences that aren’t to be trivialized, but the consequences are nothing like what has been feared and glorified in movies over the past 50 years. What we’ve learned about public risk during that time is that the forecasted nightmares resulting from nuclear accidents, even in serious accidents, simply haven’t come to fruition.

Every accident taught us something, and with every accident the NRC unveiled a new set of regulations, resulting in a system of plants that are, from the perspective of a few decades ago, much safer. Such tight regulatory oversight, while needed, drives up cost and means that utilities undertake significant financial risk with each nuclear plant they build.

If we are to keep using nuclear power even at the present rate, our risks related to waste will increase every year until storage is addressed thoughtfully and thoroughly. Monitored, retrievable storage is the safest approach to nuclear waste storage. Waste sites could be centralized and continuously monitored, and built in such a way that waste canisters could be retrieved if, for example, storage technology improves, or if it becomes economical to reprocess the waste to recover the remaining uranium and plutonium created during operation. This is where molten salt reactors can play an important roll for future nuclear energy. They can run on all the commercial nuclear waste (unused fuel) as a primary or secondary fuel source. There would be no need to bury it for thousands of years.

As a society, we accepted over 32,000 traffic accident deaths in 2013 and over 50,000+ throughout prior decades, and no one stopped driving as a result. The risk inherent in nuclear plant operation will always be present and it is one of the world’s most rigorously monitored activities, and its proven performance in delivering zero-carbon electricity is one that shouldn’t be dismissed out of fear.